In recent years, with the continuous development of the integrated circuit manufacturing technique, feature sizes of CMOS devices have been continuously decreased, and operating voltages of integrated circuits have been continuously reduced as well. Under a deep submicron process, an operating speed of analog-to-digital converters has been greatly improved. Meanwhile, the power consumption is further reduced. However, the performance of a comparator as a core component of the analog-to-digital converter becomes a bottleneck for high-speed low-power-consumption designs. It is difficult for traditional comparators to meet the requirements of speed, power consumption and low power supply voltage simultaneously.